'What Is Mathematics?' Second Edition by Courant, Robbins & Stewart[0] is a great introduction to Mathematics in general (And covers most of the main fields), b

'What Is Mathematics?' Second Edition by Courant, Robbins & Stewart[0] is a great introduction to Mathematics in general (And covers most of the main fields), but also (iirc) is good at describing the notation used. As well as that I find Wolfram Alpha[1] and Math As Code[2] good at describing some pieces of notation. Other introductory books I've found very useful are the 'Dover Books on Mathematics' introductions series, I've found their graph theory[3] and topology[4] books rather concise and clear to read -- to my knowledge they're availible at archive.org in the collection 'folkscanomy mathematics'[5]. [0]: http://www.amazon.co.uk/Mathematics-Elementary-Approach-Methods-Paperbacks/dp/0195105192/ http://www.amazon.co.uk/Mathematics-Elementary-Approach-Meth... [1]: https://www.wolframalpha.com/ https://www.wolframalpha.com/ [2]: https://github.com/Jam3/math-as-code https://github.com/Jam3/math-as-code [3]: https://archive.org/details/IntroductionToGraphTheory https://archive.org/details/IntroductionToGraphTheory [4]: https://archive.org/details/IntroductionToTopology https://archive.org/details/IntroductionToTopology [5]: https://archive.org/details/folkscanomy_mathematics https://archive.org/details/folkscanomy_mathematics